1. Field of the Invention
The present invention relates to a moving blade for use in a steam turbine, gas turbine or the like.
2. Description of Prior Arts
It is possible to save energy resources and reduce emission of carbon dioxide and so forth by suppressing a blade profile loss and a secondary flow loss generated in a turbine blade thereby increasing the internal efficiency in a turbine stage.
The well-known prior art to reduce such a turbine moving blade loss has been disclosed, for example, in JP A No. 61-232302, JP A No. 05-187202 and JP A No. 2000-345801.
The above-mentioned JP A No. 61-232302 discloses a blade profile related to a turbine cascade for use in a jet engine or a gas turbine engine and having so-called “FORE-LOADED” type velocity distribution (pressure distribution) wherein the blade profile is made in blunt nose type to increase a load per one blade and as means for reducing aerodynamic losses, the blade suction side maximum velocity point of the velocity distribution and the blade pressure side minimum velocity point are positioned at predetermined locations within a range where SX/SO is from 0.2 to 0.3, which is the respective ratios of the blade surface distance SX from a stagnation point of the leading edge along respective surfaces of the blade suction and blade pressure sides to the entire blade surface length SO from a stagnation point of the leading edge to the trailing edge along respective surfaces of the blade suction and blade pressure sides.
Further, the above-mentioned JP A No. 05-187202 discloses a blade of the turbo-machinery subject to a subsonic state, wherein the blade profile is formed such that a trailing edge portion on the blade suction side is made concave so as to suppress the momentum loss thickness in the trailing edge portion and decrease a blade profile loss.
Furthermore, the above-mentioned JP A No. 2000-345801 discloses a turbine moving blade which is formed such that it is FORE-LOADED or mid-loaded type on the inner-ring side and is AFT-LOADED type on the outer-ring side.